Control device for cooling fan for vehicle

Abstract

A cooling-fan control device for a vehicle that increases the cooling capacity of a cooling oil that cools a brake rapidly and inhibits a brake damage in a case where the brake is applied during traveling or, in addition to the above-described problem-to-be-resolved, suppresses engine horsepower consumption and avoids consumption increase, while increasing the cooling capacity of the brake cooling oil. The rotation speed of the cooling fan is controlled to obtain the higher target rotation speed of a first target rotation speed corresponding to a detected cooling oil temperature and a second target rotation speed corresponding to a detected brake operation amount. The present invention is applicable to a vehicle in which an engine power is distributed to a travel power train and a hydraulic pump, drive wheels are operated via the travel power train, and the cooling fan is actuated via the hydraulic pump.

The invention claimed is: 
     
       1. A control device for a cooling fan in a vehicle, in which cooling oil supplied to an oil-cooled brake is cooled by the cooling fan, the control device comprising:
 a sensor that detects a temperature of the cooling oil; 
 a lever that operates the oil-cooled brake; and 
 a controller that includes control logic, which when executed:
 sets a first target rotation speed of the cooling fan, the first target rotation speed corresponding to the temperature of the cooling oil; 
 sets a second target rotation speed of the cooling fan, the second target rotation speed corresponding to a brake operation amount of the lever; 
 detects whether the lever has been operated and detects whether the vehicle has stopped; 
 adjusts a rotation speed of the cooling fan to use the first target rotation speed, and not the second target rotation speed, when the controller does not detect that the lever is being operated; 
 adjusts the rotation speed of the cooling fan to use the first target rotation speed, and not the second target rotation speed, when the controller detects that the lever is being operated and the vehicle has stopped; and 
 adjusts the rotation speed of the cooling fan so as to obtain a higher target rotation speed of the first target rotation speed and the second target rotation speed when the controller detects that the lever is being operated and the vehicle has not stopped. 
 
 
     
     
       2. The control device according to  claim 1 , wherein the control device is applied to a vehicle in which an engine power is distributed to a travel power train and a hydraulic pump, and in which drive wheels are actuated via the travel power train, and the cooling fan is actuated via the hydraulic pump. 
     
     
       3. The control device according to  claim 1 , wherein the oil-cooled brake is a retarder brake. 
     
     
       4. The control device according to  claim 1 , wherein the oil-cooled brake is at least one of a retarder brake and a foot brake. 
     
     
       5. The control device according to  claim 1 , wherein
 the controller calculates an estimated oil temperature rise amount of a brake cooling oil temperature corresponding to a current operation amount of the oil-cooled brake, and 
 the controller sets the second target rotation speed based on the estimated oil temperature rise amount. 
 
     
     
       6. The control device according to  claim 1 , wherein
 the controller calculates a necessary fan rotation speed increase amount of a rotation speed of the cooling fan, 
 the controller calculates the necessary fan rotation speed corresponding to a current operation amount of the oil-cooled brake, and 
 the controller sets the second target rotation speed based on the necessary fan rotation speed increase amount.